Disk Management and Extended Partitions

[Six Underground]

I recently began migrating two of my machines from Windows XP Pro to
Windows 7 Home Premium. While there have been a couple of minor bumps
in the road, the transition hasn't been too painful.

Last night, however, I decided to do some basic disk partitioning
work. I wasn't trying to do anything fancy; just create an extended
partition in unallocated space, then define a couple of logical drives
within that extended partition.

Much to my surprise, this functionality appears to have been removed
from the graphical disk management tool. Apparently, all it would
allow me to do is create simple volumes.

Although I had no problem dropping to a command prompt and
accomplishing my goal using DISKPART, I couldn't help but wonder why
Microsoft has removed this feature from disk management.

Perhaps I'm just behind the times. Has the concept of extended
partitions and logical drives been deprecated in favor of simple
volumes? Someone please bring me up to date on this issue.

Regards,

6U

 

[Tim Slattery]

I recently began migrating two of my machines from Windows XP Pro to
Windows 7 Home Premium. While there have been a couple of minor bumps
in the road, the transition hasn't been too painful.

Last night, however, I decided to do some basic disk partitioning
work. I wasn't trying to do anything fancy; just create an extended
partition in unallocated space, then define a couple of logical drives
within that extended partition.

Much to my surprise, this functionality appears to have been removed
from the graphical disk management tool. Apparently, all it would
allow me to do is create simple volumes.

Although I had no problem dropping to a command prompt and
accomplishing my goal using DISKPART, I couldn't help but wonder why
Microsoft has removed this feature from disk management.

Perhaps I'm just behind the times. Has the concept of extended
partitions and logical drives been deprecated in favor of simple
volumes? Someone please bring me up to date on this issue.

Could it be because Win7's partitioning utility uses the new GUID
partition table instead of the old format? That format was created to
support disks larger than 2TB. Under it there's no such thing as an
extended partition, you can have up to 128 partitions. I don't know
whether that's the answer, but it fits the symptoms.

 

[Dave \Crash\ Dummy]

I recently began migrating two of my machines from Windows XP Pro to
Windows 7 Home Premium. While there have been a couple of minor
bumps in the road, the transition hasn't been too painful.

Last night, however, I decided to do some basic disk partitioning
work. I wasn't trying to do anything fancy; just create an extended
partition in unallocated space, then define a couple of logical
drives within that extended partition.

Much to my surprise, this functionality appears to have been removed
from the graphical disk management tool. Apparently, all it would
allow me to do is create simple volumes.

Although I had no problem dropping to a command prompt and
accomplishing my goal using DISKPART, I couldn't help but wonder why
Microsoft has removed this feature from disk management.

Perhaps I'm just behind the times. Has the concept of extended
partitions and logical drives been deprecated in favor of simple
volumes? Someone please bring me up to date on this issue.

If you try to create more than three partitions, an extended partition
is created with one or more logical drives. AFAIK, it takes a third
party app to create the extended partition if there are less than three
primary partitions. You might be able to remove excess primary
partitions with Disk Management once the extended partition exists.

 

[Six Underground]

AFAIK, it takes a third
party app to create the extended partition if there are less than three
primary partitions. You might be able to remove excess primary
partitions with Disk Management once the extended partition exists.

Hi Crash.

Initially, there were 3 partitions; all primaries: the system
partition, the main partition for drive C:, and a recovery partition
installed by the OEM.

Since I didn't need that recovery partition and wanted to use that
space, I deleted it, then attempted to create the extended partition,
which wasn't a Disk Management option. As such, I dropped to a
command prompt and used DISKPART to create the extended partition and
logical drives. Worked out great.

By the way, I may have been in error when I used the term "simple
volume". Now that I think about it, it may have been basic volume
instead. I got the two terms confused.

Enjoy the day.

6U

 

[Six Underground]

Could it be because Win7's partitioning utility uses the new GUID
partition table instead of the old format? That format was created to
support disks larger than 2TB. Under it there's no such thing as an
extended partition, you can have up to 128 partitions. I don't know
whether that's the answer, but it fits the symptoms.

Well, it's certainly something to think about going forward. If
applied to my current case, then the solution would have been to
dispense with the extended partition concept entirely, and instead
create two new basic/simple volumes of the appropriate size, then
assign each one a drive letter.

Interestingly, when I display the partition style for my drive in
Windows 7, it shows up as MBR format instead of GPT. I wonder if that
was the case prior to my creating the extended partition.

I have a new build coming up in which I'm going to split up a 640 GB
drive into six partitions. I think I'll try the new method in that
build and see if it even works. If I run into the 4-partition limit,
perhaps I'll try converting the partition format from MBR to GPT using
DISKPART, and then make a second attempt.

For the moment, at least, MBR partitioning continues to be available
via the DISKPART utility. As such, you can still create extended
partitions for disks up to the size limit you've mentioned, and Disk
Management still displays this information correctly.

Thanks for the info, and enjoy the day.

6U

 

[Joe Morris]

If you try to create more than three partitions, an extended partition
is created with one or more logical drives. AFAIK, it takes a third
party app to create the extended partition if there are less than three
primary partitions.

I'll agree that the "Disk Management" snapin doesn't want to create a fourth
primary partition; if you tell it to do so it quietly creates an extended
partition, then creates a logical partition. DISKPART, however, has no
problem creating four primary partitions, or creating an extended partition
without any primaries.

On the GUI tool: I hadn't noticed it (and surprisingly, neither have my
several thousand users, all of whom are professional nitpickers) but you're
right about the GUI tool not letting you explicitly request a logical
partition as was the case for earlier Windows flavors. Some quick
experimenting (Win7 Enterprise x64) shows that repeatedly asking for a new
partition in the GUI gets you a primary partition the first three times you
call for a new partition, and automagically creates an extended partition
plus a new logical partition on the fourth and subsequent calls.

You can, however, set up the disk using the DISKPART utility instead.
WARNING: DISKPART does NOT ask you "ARE YOU SURE?" when you tell it to do
something, and there's no "OOPS" command. Sample commands for the third
disk with comments not to be typed in:


SELECT DISK 2 <<< select the third disk
DETAIL DISK <<< sanity check
CREATE PARTITION EXTENDED <<< create the extended partition
<<< using all available space
CREATE PARTITION LOGICAL SIZE=25000
<<< create 25 GB partition
FORMAT FS=NTFS LABEL=FOO QUICK
<<< Format this partition
CREATE PARTITION LOGICAL <<< create another partition
<<< using all remaining space
FORMAT FS=NTFS LABEL=BAR QUICK
<<< format this partition
DETAIL DISK <<< compare output to what
<<< was shown above
EXIT


To completely wipe the existing partitions from the disk, use the CLEAN
command. (Again: there's no OOPS command, so be careful!)

Alternatively, you can use CREATE PARTITION PRIMARY four times and (on an
originally empty disk) you'll get four primary partitions.


Joe

 

[...winston]

Microsoft revised Disk Management.
The first three partitions on a drive are created as Primary.
Unless one uses Diskpart or third party software an Extended (and
subsequent logical drives) can only be created in Disk Management after the
third primary (is created).



--
....winston
msft mvp mail


"Six Underground" wrote in message

AFAIK, it takes a third
party app to create the extended partition if there are less than three
primary partitions. You might be able to remove excess primary
partitions with Disk Management once the extended partition exists.

Hi Crash.

Initially, there were 3 partitions; all primaries: the system
partition, the main partition for drive C:, and a recovery partition
installed by the OEM.

Since I didn't need that recovery partition and wanted to use that
space, I deleted it, then attempted to create the extended partition,
which wasn't a Disk Management option. As such, I dropped to a
command prompt and used DISKPART to create the extended partition and
logical drives. Worked out great.

By the way, I may have been in error when I used the term "simple
volume". Now that I think about it, it may have been basic volume
instead. I got the two terms confused.

Enjoy the day.

6U